Abee L. Boyles is a Ph.D. student in the Duke University Program in Genetics and Genomics. Her dissertation focuses on the genetics of neural tube defects and Chiari Malformation.
Candidate gene analysis in human neural tube defects
Article first published online: 6 APR 2005
Copyright © 2005 Wiley-Liss, Inc.
American Journal of Medical Genetics Part C: Seminars in Medical Genetics
Special Issue: Neural Tube Defects
Volume 135C, Issue 1, pages 9–23, 15 May 2005
How to Cite
Boyles, A. L., Hammock, P. and Speer, M. C. (2005), Candidate gene analysis in human neural tube defects. Am. J. Med. Genet., 135C: 9–23. doi: 10.1002/ajmg.c.30048
- Issue published online: 18 APR 2005
- Article first published online: 6 APR 2005
- neural tube defects;
- candidate genes;
- gene mapping
Biochemical and developmental pathways, mouse models, and positional evidence have provided numerous candidate genes for the study of human neural tube defects. In a survey of 80 studies on 38 candidate genes, few found significant results in human populations through case-control or family-based association studies. While the folate pathway has been explored extensively, only the MTHFR 677C > T polymorphism was significant, and only in an Irish population. Developmental pathways such as the Wnt signaling pathway and Hox genes have also been explored without positive results. More than 90 mouse candidates have been identified through spontaneous and knockout mutations, but only the T locus (mouse Brachyury gene) showed association in an initial study that was not confirmed on follow-up. Positional candidates have been derived from cytogenetic evidence, but preliminary genomic screens have limited power due to small sample sizes. Future studies would increase their power to detect association by using more samples. In addition a clarification of the phenotype would be beneficial as many studies used different inclusion criteria. Incorporating several types of data could highlight better candidates, as would looking beyond the traditional sources for candidate genes. Recent studies of an energy metabolism gene (UCP2) and vitamin B metabolism (Transcoalbumin) have produced promising results. Utilizing other model organisms may also be beneficial, as in a recent study from a chick model of NTDs in NCAM1. New approaches combined with traditional methods and increased sample sizes will help prioritize human NTD candidate genes and clarify the complex etiology of this condition. © 2005 Wiley-Liss, Inc.